A tender car (or “rail tender”) is a special rail vehicle hauled by a rail locomotive. The tender car contains the locomotive's fuel. Some rail vehicles are fueled by liquid natural gas (LNG), which means that the tender car is an LNG tender car, which typically includes a pump that is submersed within LNG in a tank. The submerged pump is configured to pump the LNG to the rail locomotive for power.
LNG rail tenders are relatively uncommon and the rail regulatory agencies still have not developed a set of regulations specifically for LNG rail tenders. A legitimate concern is the safety of the rail tender in the event of a rail accident such as derailment. In such an accident, the pipe that is coupled to the LNG tank may rupture, fracture, or rip from the tank, which might lead to release of LNG and subsequent jet or pool fires. This would obviously be undesirable and dangerous.